1. Technical Field
The present disclosure relates to real-time transport control protocol and more specifically to implementing real-time transport control protocol to obtain end-to-end session information.
2. Introduction
Troubleshooting media performance issues in a communication session can be an extremely difficult task. When users experience poor audio or video quality during a call, they are typically unable to identify the source of the problem, particularly as the size and complexity of the call increases. Without knowing the source of the problem, users are often left with few—mostly imprecise—troubleshooting measures, such as ending the call to establish a new call, or incrementally muting the phones to isolate the troublemaker. But many times, the problem persists as users exhaust their troubleshooting options. Overall, the process can be long and the experience frustrating and the outcome costly.
Engineers similarly have great difficulty identifying the source of the problem in a call. The resolution of call-quality problems is a formidable challenge precisely because the availability of relevant information is scarce: gathering the necessary information to perform a thorough analysis can be an expensive and onerous proposition. For example, often times, an engineer will receive a complaint from a user reporting poor audio or video quality during a past call. The engineer begins the troubleshooting process by trying to understand the problem. What is the model of the phone being used? Is it a handset or a speaker phone? Is the problem a recurring one? Is the phone shuffling or is a gateway involved? What is the codec being used? Is the gateway transcoding? Is there a bridge involved? Is there packet loss? What is the network topology? Answers to these and many other questions are essential to understanding and troubleshooting the problem. Yet, currently, there are no existing tools that push this information out to the phones or session endpoints. Instead, engineers typically must deploy sniffers on the network to record the actual media received at a particular endpoint, an expensive and laborious process.
Real-time transport control protocol (RTCP) packets can be analyzed to obtain some relevant information. RTCP provides feedback on the quality of data distribution in a real-time transport protocol (RTP) flow. In particular, RTCP packets provide a summary of the quality over a single hop of the media path at the application layer. However, except in the limited case of a pair of shuffling IP phones, the end-to-end media traverses through multiple hops. Consequently, RTCP packets generally do not provide an end-to-end summary of the quality of a session. Thus, engineers do not have effective tools or techniques for measuring the end-to-end quality of a media session. And while session quality for a media session is experienced on an end-to-end basis, engineers are unable to determine which element in the network path is creating the problem when the problem arises.